There has been a body supporting tool such as an office chair and car seat, which supports a body with a cushioned body supporting surface such as a backrest and seating surface. Other than the body supporting tool, even an object supporting tool is sometimes required to have a cushioned object supporting surface to support a three-dimension object like a body. Such a cushioned object supporting surface often comprises a core member such as a metal frame, a foamed elastic member such as urethane foam, and an elastic body which covers them.
Recently, a well cushioned chair provided with a body supporting surface made of knitted or woven fabric mesh sheet instead of inner urethane foam is commercially available, and new product designs are appearing (See JP2007-117537-A and JP2006-132047-A). JP2007-117537-A discloses a chair having a backrest made of a sheet member having a saclike periphery through which a bone of a core member is inserted for a support JP2006-132047-A discloses a chair provided with a seating surface of a warp-knitted fabric manufactured by a double raschel warp knitting machine. The warp-knitted fabric is cushioned with the inserted weft made of elastic yarns. In both publications, only one kind of each fabric structure and each yarn is disclosed.
If a mesh sheet is used and the metal frame is made planar rectangle, the object supporting surface becomes planar, too. However, the object such as a body to be supported with the object supporting surface has a three-dimensional shape. The planar object supporting surface, even if well cushioned, tends to elastically deform greatly to support a prominent portion of an object such as a body so that a great reaction force is continuously generated to be applied to the body at the supporting portion. It is important for chairs to be comfortable that the elasticity, which means the initial tension, is adjusted properly at each portion by making the supporting surface fit to the shape of the contact surface of the object to be supported.
In the techniques disclosed in the above-described patent documents, hard work to assemble intricately-shaped frames and mesh fabrics under a high tension condition is required to optimize shape and elasticity of the supporting surface.
Accordingly, it could be helpful to provide a three-dimension fabric which can be used to make a desirable structure easily and of which object supporting surface can be easily shaped and elasticized at each portion, even if intricately-shaped frames are not used.
Besides, it is not a good solution that different materials and different fabrics are assembled by sewing or bonding at each portion on a supporting body. Namely, such a solution is not practical because of the high cost as well as the difficulty in sewing or bonding the mesh sheets.